Hedge trimmer



J. C. DETTRA HEDGE TRIMMER Oct. 23, 1923.

l N VEN TOR Arran/vers WITNESS mmd,

2 Sheets-Sheet 2 Il lll lll lll ll lll!! 17T TORNEYS Oct. 23, 1923.

J. C. DETTRA HEDGE TRIMMER Filed July 50. 1921 s# WWP/MK Patented 0er. 23, i923.

iiiai rar JOHNA o. narran', or eens, rririivsvnviiiiga.

tetes HEDGE marianna Appiicatioii sied July 3o,

being to provide a hedge trimmer ot' light vet sturdy construction which isadapta'ble tor use in various positions, thereby enabling the trimmer to be utilizedconveniently in trimming'the sides, tops and other portions or" a hedge. v

Further objects of the invention are the provision in a hedge trimmer ot the character aforesaid, of Vmeans whereby the actuating mechanismA may be adjusted to various po sitionswith respect to the relatively reciprocating cutting'blades, thus enabling the operator by suitable adjustment of said mechanism to readily .operate the trimmer in different positions required tor the trimming ot a hedge, the adjustment ot the actuating mechanism referred to being ettective to bring the operating handle, through the medium of which the power is supplied to-cause relative reciprocationot the cutting blades, to positions suitable Jfor maximum convenience of operation in accordance with the position Yin Vwhich Vthe blades are to be maintained.

A still further object of the invention is to .so proportion and design the teeth. of the cutting blades so as to enhance the cutting power of the blades and enable theoperator to trim off the branches or shoots of the hedgev with a minimum expenditure of ettort, sothat the machine may be used in the trimming of hedges having relatively thick shoots or branches for a considerable period of time without unduetatigue.

The invention further comprehends the general simplification of machines ot this general character andthe design, construction and arrangement of the various parts thereof so as to produce a light and efficient machine which may be conveniently operated Jfor the purpose intended and which is not liable to getV out of order or be damaged in use.

The invention further includes all of the Y192i. serial No. 488,541.

Vothervarious objects Vandnovel vfeatures, of`Y construction` andarrangement hereinafter s f more definitely specified and described. c

In the accompanying drawing in which is shown a preterredembodiment of the invention, Fig. l is a side elevation thereof] illus trating onemethod ot utilizing the machine in trimming the 'side of a' Hedge, the hedge H being indicated lin broken lines in said figure as lying between the observer and the f machine. Fig. 2 is a Afront elevation of the machine shown in Fig. l the actuatingmechanism in these figures being shown as ad gusted to a position in which the operating handle is in a plane. at right anglesto the plane of the cutting blades thereby placing the machine in themost convenient condi- -tion for operation when the blades are to be maintained in a substantially vvertical position as in trimming the sides` of a hedge. Fig. 3 is a top plan View ofthe machine with the actuating mechanism adjusted to a position in which the operating'hand'le is in a plane parallel with the plane ofthe cutting blades, thereby placing the 'machine in the most convenient condition tor operation When the blades are to be maintained in a substantially horizontal position as in trimming top of a hedge-H as indicated in said igure, and Fig. ais a Yfront elevationv ot the machine adjusted as shown in Fig. 3. F ig. 5 Vis Ya fragmentary detail View of a portion of one of thecutting blades removed from themachine'. i 1

`leferring Vmore particularly to the I form ot the invention illustrated, the same comf prises a pair of cutting blades l .and 2v each having `a1 longitudinally Yextending body portion and outwardly projecting VVsubstantially triangular teeth 3. The Vblade 2 is rigidly secured, as by screws 5,- to a sup-l porting' bar lwhich extends under the body portion of the blade and projects foray suitable distance thereabove \vvhen' viewed as 'inlligs l and 2, this bar 'affording a rigid sup- `-porttor the-relativelythin and more or less' VflexibleYbladeto-maintain thefsame in properl 1 alignment. The blade l is larranged for rel-v 'ative reciprocation with respect to'thebladeV pret'erably by providing-the yformer .with Y a pluralityot slots 8 through-eachv'vof which extends ascrew 9 .having/a large head over'- ylyingthe edges 'of theqslot, the end ottheV screw passing throughvthe blade 2 being rigidly seated inthe supporting bar thereby holdingthe blades in sliding Contact...V Riv# eted or otherwise secured to the supporting bar are a plurality oi handles 10 by means of 4which the operator is enabled to eonreniently support and guide the blades under certainconditions of operation.

For effecting` they reciprocation or the blade 1, suitable means are provided which may preferably comprise a relatively large 0'eail Wheel 13 sinziported on a shaft 141- rob L A tatably mounted in a journal box 15 rigidly secured toa supoorting member 16 pre/ferably in the form Yof a flat bar. rlfhis inember Which is detachably supported from 1f e bar 6 as hereinafter described, is also e1 tive to support another journal box 1S in Which is journaled a shaft 19, carrying on one end a. pinion 2O meshing` with the 13 and at the other end a small balance or fly Wheel 21 to which is secured an outwardly projectingJ crank pin 22 cooperating; with one end of pitman 24;, the other end ot' which carries slotted or jaw-like cross head 25. ilinoperating handle is rotata bly supported on a crank secured to vthe gear Wheel .15, by means of which the gear train and balance Wheel maybe rotated to cause reciprocation of the pitman. lGrease cups 33 are preferably provided to taire care of the lubrication ol the shafts.

The cutting blade 1 is provided at one end with a lug or ear 35 which extends out wardly from the body oi? the blade and is Yturned up near its end at right angles lo the plane of the blade and drilled tor the passage ot a pivot pin, and tor assisting in holding` that portion ot the blade adjaeei the lug in contact With the ot ier blade and in proper alignment7 a channel-shaped guide 36 is preferablyV secured to the support 6 as by screws 37, to surround both blades and the support on three sides.

Under operative conditions the member 16 which carries the actuating; mechanism is supported Ytrom that end of the simperting` bar 6 which projects beyond the blades and means are `provided for effecting a connection therebetween in such man-*1er that the member may be operatively ad isted so as to bring the handle 3() into a plane parallel to thev plane or the cutting` blades orv into a plane at right angles thereto -so as to position the handle Yin the most convenient position `for manipulation. VMore specilically; when it is desired to V'arrangethe handle in a plane parallel to the plane of' the cutting blades, as shor-,f'n

"ot the 'supportingv bar 6 conveniently by reis connected directly to the projectine;

inoyable' thumb screws 40', the parts being vbrought together 'With 'their Widest faces Yin 3 and theend of the'member l? 1,4m ,fies

supporting bar 6, in elect forms :i substantial continuation ot Vthe supporting' ar, the relative position ot the actuating` mechanism and the lufr being such that the cross Vhead 25 ot the pitman may be connected directly to the lug by a pivot pin L11 remorably maintained in position by cotter pins 412, a similar pin serving to hold the other end oit the pitman on the crank pin which latter is locater at a proper die tance Yfrom the center of the balance wheel 21 to give the desired stroke or reciprocation to the cuttingblade 1 when the gears are rotated. TWith the parts adjusted ii this manner, the machine may be con 'eniently employed in trimming; the top oi a hedge, as shown in Fig. 3, being prefere-.bl5Y supj-)orted by a sling 475 having' snap heele; 6 at'is ends engaging respectively in an ye 47 at the end ot tl e handle 10 and in n eye Ytoi-med in a lug' L18 secured to auf. .bout midway between the. ends oi the supporting bar .ln use the sling is passed around the operatoi"s neck and the machine steadied an guided by one of ythe handles l() With the left hand While the i'iiht is used to rotate the operating` handle 30.

lV hen however it is desired to utilize the machine in an upright or substantially up right position as in trimming ythe side of hedge, the sling-jY is disengaged and the actuating mechanism so adjusted as to brine; the operating` handle into a plane .at right to that ofthe blades. To effect this adjustment, a bracket 50' is employed which corniY rises an l -shaped plate formed with its flanges at right angles toY each other and haring spaced holes drilled near the outer edges thereof and arranged'to register respectively with the holes in lt ie projecting' end oli the supportinev bar 6 and in the enfl oil the member 1G. Thus by securing?T one oi the flanges to the end oic the supporting bar by thumb screws 10 and the lower end of" the menilei: 15 to the other 'flange ol" the biacl'et,'tlie supporting' bar t3 and the meinber 16 may be ojeratiyely connected with their respective Wider 'acee at right si.. les to each otlie., thus bringing` the operai handle oit theactuating mechanism into plane normal to that of the cuttingv blade.

n order. houwe-rTv to'eiect an opera'tire ion under these 1 Y: pitman L i Wh, i

angle, to the ia fs and adapte(`L te i.. into and b; received between the yairs et the cresshead 25, a pivot pin s1 i ieingj utilized rto elieet an operative 'connection t ereb een.' i it Iwill be evident that the interposition oit the auxiliary crosshead 523 between the pitman and the lug would serve to substantially extend the effective length of the former and thus disturb lthe desired relation between the cutting blades in the absence ofthe provision of means for effecting a corresponding shortening of the pitman, and I therefore prefer to provide the end of the pitman opposite to that having the crosshead Q5 with a pair of holes 5d each adapted for the reception of the crank pin, t-he distance between the centers of the holes corresponding to the distance between the centers of the pivot holes in the auxiliary crosshead 53, so that when the latter is employed the fc'rank pin may be engaged in the lowermost hole of the pit` man thus shortening' its effective length by an amount equal to the elongation produced by the employment of the auxiliary crossliead.

For supporting the weight of the machine when utilized in a substantially upright position, I provide a curved shoulder rest positioned on an upright 61 preferably near the lower end thereof, the upper end of the upright being removably attached to a brace 62 which extends to and is in turn removably attached adjacent the upper end of the member 16 as best shown in Fig. 1 the operative connection of these several members to each other being preferably effected through the medium of suitable thumb screws and plurality of holes for their passage being provided in the upright. rI`hus by relative adjustment of the several parts just described the shoulder rest' may be brought to a. position to comfortably rest on the shoulder of the operator to support the weight of the machine, which is held upright and to some extent guided through the medium of the handle l0 and a leg rest 65 removably secured at a suitable point to the supporting bar 6 and carrying a curved yoke 66 adapted torest against the operator`s thigh.

In the construction of hedge cutting machines having relatively reciprocatory cutting blades it has hitherto been customary to arrange the teeth, which are ordinarily of substantially triangular form, in proximity I to each other, the side edges of the respective f teeth closely approaching the opposite edges of the adjacent teeth at'therroots thereof so that the space between any two teeth is in the form of a. pointed V. I have found, however, that by constructing the cutting blades with teeth rather widely separated instead of in close proximity to each other, that it is possible in a machine of this char-v acter to mate-rially enhance the ability thereof to cut through the shoots or branches of the hedge with a considerably smaller expenditure of power than is possible where the teeth are setclosely together, or, viewed 'in another aspect, to satisfactorily, cut

through considerably larger branches. or shoots with vagiven expenditure of power. lilore specifically,`and as best shown in Fig. 5, I prefer `to space apart the teeth 3 atv their rootsforra "distance at' leastr equal to the width of the root of each tooth and I find that in practice good results are attained when the spacing between the teeth is in creased to a distance nearly equalrto twice the width of the root. of each tooth, or, in other words, referring to Fig. 5, Ifprefer to make the distance a substantially equal to the diameter of the circular path traversed by the crank pin 22 and at least'equal to and preferably considerably greater than the distance Z2. By constructing theblades in this manner, I find in practice that as the machinev is moved alongthe hedge the shoots or branches thereof are lgathered inthe spaces between the teeth during the time when the teeth on the respective blades are more or less in corresponding aligment and the pitman is either approaching or has just passed the limit of'its stroke in either direc tion, However, as the reciprocating blade is moved so as to bring its teeth more and more outfof alignment with the teeth on the stationary blade, it gathers speed as the speed of revolution of the crank pin increases and as the cutting edges of the ,teeth of the reciprocating blade gradually overlap the cutting edges of the corresponding teeth on the stationary blade, the shoots and branches are sheared off easily and cleanly and with a minimum expenditure of effort.

l/Vhile I have described and illustratedl herein with considerable particularity a preferred form of my invention I do not thereby desire or intend to limit myself to any precise details of construction and arrangement of the various parts as the same may be modified or varied in minor particulars from the precise embodiment disclosed as may be desired without departing from the spirit and scope of the invention as defined in the appen-ded claims. n

Having thus described my invention I claim and desire to protect by Letters Patent of the United States:

l. In a machine of the class described the combination with a bar and a pair of cutting blades one mounted for .reciprocation longitudinally of the bar of a bracket detachably secured to the bar at one end, a member for detachable connection to the bracket or bar, meshing gears carried by the member, saidv member being adjustable relativeto the bar to support'the gears for rotationV in a plane either parallel with or at right angles to the ated by the gears, and means for connectingV the pitman to one of the cutting blades when the gears'are in either position relative to the blades.`

.eg-5 narines y Y 2. ln a device `of the class described the combination with a bar, a cutting blade thereon, and a second blade mounted for re-1 ciprocation on the cutting blade, ofmeshing Y by the blades, means rotatable with the gears' for actuating the saine, a ypitman actuated by the gears, means for connecting the pitman to the reciprocating blades when the gears are in either position relative to the blades, a brace adjustably connected to said means, an upright adjustably connected to the brace, and ashoulder rest extending from the upright, said rest and the gear operating means being. positioned adjacent opposite sides respectively of the operator.

3. In a device of theclass described the combination with a bar, a cutting blade thereon, and a second cutting blade mounted for reciprocatiom-of meshing. gears, a crank arm for rotating the gears, a member supporting the gears, a detachable bracket engaging the said Vmember and bar for holding the gears and the crank arm for rotation in planes parallel with the plane of cut by the blades, an ear upon the reciprocating blades, a pitmanoperated by thegears, and a universal connection between and detachably connected to the pitman and ear.

4. In a device of the class described the combination with afmember, meshing gears thereon, and a crank arm for rotating the gears, of: a pitman actuated by the gears, a cutting element actuated by the pitman, a handle upon said member, a brace adjustably connected to the member, ain upright adjustably connected to the brace, and a shoulder rest extending from the upright, said upright and crank arm. being spaced apart to extend close to opposite sides respectively of the operator.

ln witness whereof, l have hereunto set my hand this 29th day of July, A. D. 1921.

JOHN C. DETTRA. 

